body{
	margin:0;
}
div.cartridge{
	float:left;
	width:250px;
	height:250px;
	position:relative;
}
div.play_btn{
	box-sizing:border-box;
	border:2px solid #000;
	height:40px;
	border-radius:20px;
	line-height:36px;
	text-align:center;
	background-color:#000;
	color:#fff;
	position:absolute;
	visibility:hidden;
	opacity:0.6;
	width:150px;
	left:50px;
	font-weight:800;
	font-family:Lucida Console;
}
div.cartridge:hover div.play_btn{
	visibility:visible;
}
div.play_btn:hover{
	background-color:#fff;
	color:#000;
	opacity:1.0;
}
div.wasm_play_btn{
	top:80px;
}
div.js_play_btn{
	bottom:80px;
}
div.wrapper{
	width:750px;
	margin:auto;
}